In an apparatus, a collimated-beam irradiating unit irradiates on the target a substantially collimated beam with a size thereon. A first pickup unit causes the photodetector to pick up through the imaging optics a first image of the target while the substantially collimated beam is being irradiated on the target by the collimated-beam irradiating unit. A measuring unit measures size information indicative of the size of the collimated beam being irradiated on the target based on the picked-up second image. A distance determining unit determines a distance between the apparatus and the target based on the measured size information of the collimated beam.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An apparatus for optically reading out, through an imaging optics, information by a photodetector, the information being attached to a target, the apparatus comprising: a collimated-beam irradiating unit configured to irradiate on the target a substantially collimated beam with a size thereon; a first pickup unit configured to cause the photodetector to pick up through the imaging optics a first image of the target while the substantially collimated beam is being irradiated on the target by the collimated-beam irradiating unit; a measuring unit configured to measure size information indicative of the size of the collimated beam being irradiated on the target based on the picked-up first image; and a distance determining unit configured to determine a distance between the apparatus and the target based on the measured size information of the collimated beam, wherein the imaging optics has a predetermined field angle, and the collimated-beam irradiating unit is configured to irradiate on the target the substantially collimated beam along one edge of a field defined by the field angle of the imaging optics.
2. An apparatus according to claim 1 , wherein the collimated-beam irradiating unit is provided with a light source and a condenser lens with a predetermined focal point, the light source being disposed at the focal point of the condenser lens to be coaxial thereto.
3. An apparatus according to claim 1 , wherein the substantially collimated beam has a predetermined color, further comprising an illuminating light irradiating unit configured to irradiate illuminating light with a predetermined color on the target, the color of the substantially collimated beam being different from that of the illuminating light.
4. An apparatus according to claim 1 , further comprising a storing unit configured to store relational data indicative of a relationship between at least one item of the size information and corresponding at least one value of the distance between the apparatus and the target, wherein the distance determining unit is configured to determine the distance between the apparatus and the target based on the relational data and the measured size information.
5. An apparatus according to claim 1 , further comprising a determining unit configured to: determine whether the determined distance is within a predetermined range; and when determining that the determined distance is out of the predetermined range, send a notice representing that the determined distance is out of the predetermined range.
6. An apparatus according to claim 1 , further comprising: an illuminating light irradiating unit configured to irradiate illuminating light on the target; and a second pickup unit configured to cause the photodetector to pick up through the imaging optics a second image of the target while the illuminating light is being irradiated on the target and the substantially collimated beam is kept off after the pickup of the first image.
7. An apparatus according to claim 6 , further comprising an exposure time determining unit configured to determine an exposure time of the photodetector depending on the determined distance between the apparatus and the target, wherein the second pickup unit is configured to expose the photodetector based on the determined exposure time to pick up through the imaging optics the second image of the target.
8. An apparatus according to claim 1 , further comprising: an illuminating light irradiating unit configured to irradiate illuminating light on the target, the first pickup unit being configured to cause the photodetector to pick up through the imaging optics the first image of the target while the substantially collimated beam and the illuminating light are being irradiated on the target by the collimated-beam irradiating unit and the illuminating light irradiating unit, respectively; and a decoding unit configured to decode the information based on the first image.
9. An apparatus according to claim 1 , further comprising a focal point adjusting unit configured to automatically adjust a focal point of the imaging optics based on the determined distance between the apparatus and the target.
10. A method of optically reading out, through an imaging optics installed in an apparatus, information by a photodetector installed therein, the information being attached to a target, the method comprising: irradiating on the target a substantially collimated beam with a size thereon; causing the photodetector to pick up through the imaging optics a first image of the target while the substantially collimated beam is being irradiated on the target; measuring size information indicative of the size of the collimated beam being irradiated on the target based on the picked-up first image; and determining a distance between the apparatus and the target based on the measured size information of the collimated beam, wherein the imaging optics has a predetermined field angle, and the collimated-beam irradiating step irradiates the target with the substantially collimated beam along one edge of a field defined by the field angle of the imaging optics.
11. An apparatus for optically reading out, through an imaging optics, information by a photodetector, the information being attached to a target, the apparatus comprising: a collimated-beam irradiating unit configured to irradiate on the target a substantially collimated beam with a size thereon; a first pickup unit configured to cause the photodetector to pick up through the imaging optics a first image of the target while the substantially collimated beam is being irradiated on the target by the collimated-beam irradiating unit; a measuring unit configured to measure size information indicative of the size of the collimated beam being irradiated on the target based on the picked-up first image; and a distance determining unit configured to determine a distance between the apparatus and the target based on the measured size information of the collimated beam; an illuminating light irradiating unit configured to irradiate illuminating light on the target, the first pickup unit being configured to cause the photodetector to pick up through the imaging optics the first image of the target while the substantially collimated beam and the illuminating light are being irradiated on the target by the collimated-beam irradiating unit and the illuminating light irradiating unit, respectively, the information being a two-dimensional code including an error-correcting code, the error correcting code allowing correcting errors included in the two-dimensional code depending on a predetermined error correction level of the two-dimensional code; and a decoding unit configured to: determine whether a determination level depending on a total area of a dirty or damaged portion and a superimposed portion in the first image with respect to a whole area of the two-dimensional code exceeds the error correction level, the superimposed portion being a portion on which a component of the substantially collimated beam in the first image and that of the two-dimensional code therein are superimposed; and decode the information based on the first image when it is determined that the determination level does not exceed the error correction level.
12. An apparatus according to claim 11 , wherein the collimated-beam irradiating unit is provided with a light source and a condenser lens with a predetermined focal point, the light source being disposed at the focal point of the condenser lens to be coaxial thereto.
13. An apparatus according to claim 11 , wherein the substantially collimated beam has a predetermined color, further comprising an illuminating light irradiating unit configured to irradiate illuminating light with a predetermined color on the target, the color of the substantially collimated beam being different from that of the illuminating light.
14. An apparatus according to claim 11 , further comprising a storing unit configured to store relational data indicative of a relationship between at least one item of the size information and corresponding at least one value of the distance between the apparatus and the target, wherein the distance determining unit is configured to determine the distance between the apparatus and the target based on the relational data and the measured size information.
15. An apparatus according to claim 11 , further comprising a determining unit configured to: determine whether the determined distance is within a predetermined range; and when determining that the determined distance is out of the predetermined range, send a notice representing that the determined distance is out of the predetermined range.
16. An apparatus according to claim 11 , further comprising: an illuminating light irradiating unit configured to irradiate illuminating light on the target; and a second pickup unit configured to cause the photodetector to pick up through the imaging optics a second image of the target while the illuminating light is being irradiated on the target and the substantially collimated beam is kept off after the pickup of the first image.
17. An apparatus according to claim 16 , further comprising an exposure time determining unit configured to determine an exposure time of the photodetector depending on the determined distance between the apparatus and the target, wherein the second pickup unit is configured to expose the photodetector based on the determined exposure time to pick up through the imaging optics the second image of the target.
18. An apparatus according to claim 11 , further comprising a focal point adjusting unit configured to automatically adjust a focal point of the imaging optics based on the determined distance between the apparatus and the target.
19. A method of optically reading out, through an imaging optics installed in an apparatus, information by a photodetector installed therein, the information being attached to a target, the method comprising: irradiating on the target a substantially collimated beam with a size thereon; causing the photodetector to pick up through the imaging optics a first image of the target while the substantially collimated beam is being irradiated on the target; measuring size information indicative of the size of the collimated beam being irradiated on the target based on the picked-up first image; determining a distance between the apparatus and the target based on the measured size information of the collimated beam; irradiating illuminating light on the target, the causing step causing the photodetector to pick up through the imaging optics the first image of the target while the substantially collimated beam and the illuminating light are being irradiated on the target by the collimated-beam irradiating step and the illuminating light irradiating step, respectively, the information being a two-dimensional code including an error-correcting code, the error correcting code allowing correcting errors included in the two-dimensional code depending on a predetermined error correction level of the two-dimensional code; determining whether a determination level depending on a total area of a dirty or damaged portion and a superimposed portion in the first image with respect to a whole area of the two-dimensional code exceeds the error correction level, the superimposed portion being a portion on which a component of the substantially collimated beam in the first image and that of the two-dimensional code therein are superimposed; and decoding the information based on the first image when it is determined that the determination level does not exceed the error correction level.
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January 31, 2006
July 21, 2009
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